With the development of science and technology, virtual display technology is being increasingly used in the productions and lives of people. Specifically, a head-mounted display device (also referred to as a virtual display device) is the most widely used. The head-mounted display device is a three-dimensional display that guides a user to create a feeling of being in a virtual environment based on differences between pieces of information obtained by left and right eyes of the user. The display principle is that screens for the left and right eyes display images to the left and right eyes respectively. The eyes of the user obtain the information with difference, and then the user generates a stereoscopic feeling in his or her mind. When the user wears the head-mounted display device, a virtual world with a strong stereoscopic effect can be viewed.
For head-mounted display devices in related technologies, difficulty in interpupillary distance adjustment needs to be reduced.